Don't know where Hidden Valley road is but we were up behind Pikes Peak last week and spent a few days at FS Crags campground. 18 sites also sites along the stream. Gets busy during the weekend but we were up there during the week. Only one other camper and the host. The Crags trailhead is from there, nice hike. This is just a few hundard yards south of the Mueller State park entrance on your left. 3 miles up to 10,000 feet.

Sounds cool! I tried to look up that campground...got a link or GPS coordinates?